What is termed the PTP protocol (PTP: Precision Time Protocol), which is defined in the IEEE 1588 standard (IEEE: Institute of Electrical and Electronic Engineers), is the protocol currently favored for synchronizing the clock and phase of clock generators via asynchronous networks. The cited standard basically makes a very high synchronizing accuracy possible. However, the hardware requirements for achieving said synchronizing accuracy are not precisely specified in the present version of said standard, namely “IEEE Std 1588™-2002, IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems”, dated Nov. 8, 2002.
The references made below to said standard relate to the aforementioned version, whose disclosure content is deemed to be included in the present document on a reference-specific basis.
The achievable synchronizing accuracy has hitherto been limited owing in particular to what is termed a software jitter occurring while the time stamps are being provided and read by an IEEE 1588 protocol stack implemented by software means. Said jitter is due mainly to the unsteady processing sequence of the responsible protocol routines, which are generally disrupted by the operating system by numerous what are termed interrupts. Said software jitter is within the scope of the IEEE 1588 standard referred to also as protocol stack delay fluctuation. A synchronizing accuracy only in the order of 1 μs to 100 μs has in practice proved to be attainable in this manner.